Hi All,
Lots of great posts in this thread. My Extra is coming along, although I have been into other things this summer. Building season is close and I will get back to the project soon. At this point I have the main wings sheeted, ailerons cut out, leading and trailing edges installed shaped and sanded, and the ends capped. Also while doing the sheeting operations I jumped ahead and sheeted the tail feathers. I know Rate1 has been interested in some FG parts. I got a nice FG cowl and hatch from Stan's Fiber Tech. Good prices too! [link=http://www.stansfibertech.com/]http://www.stansfibertech.com/[/link]

There is a great AMA article on a scratch built Extra they did a few years ago. [link=http://www.modelaircraft.org/mag/hurley/hurleyindex.asp]http://www.modelaircraft.org/mag/hurley/hurleyindex.asp[/link]
I found part 2 on Sheeting foam wings to be the most helpful. Three things that I took away from that section was the best method for joining your 1/16 balsa sheet together to form the skin, filling in the stress plate bay with scrap foam, and capping the ends of the tube socket with 1/8-inch light ply.

The method they used to join the sheets is really slick. You tape the sheets together with blue painter’s tape on one side. Then flip it over and let it hang over the edge of the table and run a bead of thick CA in the seam, then just slide it flat on the table and wipe the excess. My only advice here is to let it setup (5-10 secs) and flip it over onto wax paper and remove the tape and scrap or lightly sand off any CA that got on the other side. If you let it fully harden than the tape will get stuck in a few spots and any lumps will be had to remove. This method is way better than just pinning the sheets down and dripping thin CA on the joints which will result in lots of hard CA on the back side that cannot be removed.

Filling in the stress plate bay gives the stress plate two surfaces to adhere to for more strength on the part that the wing tube is relying on to stay connected to the foam and the rest of the wing. Capping the tube socket will keep the wing tube from migrating into the foam if it ever got loose.

When I get a chance I will dig up some pics of the progress so far.